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Message-ID: <20240919170737.3oe2teklabpz54hx@AALNPWDAGOMEZ1.aal.scsc.local>
Date: Thu, 19 Sep 2024 19:07:37 +0200
From: Daniel Gomez <da.gomez@...sung.com>
To: Kris Van Hees <kris.van.hees@...cle.com>
CC: <linux-kernel@...r.kernel.org>, <linux-kbuild@...r.kernel.org>,
<linux-modules@...r.kernel.org>, <linux-trace-kernel@...r.kernel.org>, Nick
Alcock <nick.alcock@...cle.com>, Alan Maguire <alan.maguire@...cle.com>,
Steven Rostedt <rostedt@...dmis.org>, Sam James <sam@...too.org>, Masahiro
Yamada <masahiroy@...nel.org>, Luis Chamberlain <mcgrof@...nel.org>, Masami
Hiramatsu <mhiramat@...nel.org>, Nick Desaulniers <ndesaulniers@...gle.com>,
Jiri Olsa <olsajiri@...il.com>, Elena Zannoni <elena.zannoni@...cle.com>
Subject: Re: [PATCH v10 2/4] kbuild: generate offset range data for builtin
modules
On Fri, Sep 06, 2024 at 10:45:03AM -0400, Kris Van Hees wrote:
> Create file module.builtin.ranges that can be used to find where
> built-in modules are located by their addresses. This will be useful for
> tracing tools to find what functions are for various built-in modules.
>
> The offset range data for builtin modules is generated using:
> - modules.builtin: associates object files with module names
> - vmlinux.map: provides load order of sections and offset of first member
> per section
> - vmlinux.o.map: provides offset of object file content per section
> - .*.cmd: build cmd file with KBUILD_MODFILE
>
> The generated data will look like:
>
> .text 00000000-00000000 = _text
> .text 0000baf0-0000cb10 amd_uncore
> .text 0009bd10-0009c8e0 iosf_mbi
> ...
> .text 00b9f080-00ba011a intel_skl_int3472_discrete
> .text 00ba0120-00ba03c0 intel_skl_int3472_discrete intel_skl_int3472_tps68470
> .text 00ba03c0-00ba08d6 intel_skl_int3472_tps68470
> ...
> .data 00000000-00000000 = _sdata
> .data 0000f020-0000f680 amd_uncore
>
> For each ELF section, it lists the offset of the first symbol. This can
> be used to determine the base address of the section at runtime.
>
> Next, it lists (in strict ascending order) offset ranges in that section
> that cover the symbols of one or more builtin modules. Multiple ranges
> can apply to a single module, and ranges can be shared between modules.
>
> The CONFIG_BUILTIN_MODULE_RANGES option controls whether offset range data
> is generated for kernel modules that are built into the kernel image.
>
> How it works:
>
> 1. The modules.builtin file is parsed to obtain a list of built-in
> module names and their associated object names (the .ko file that
> the module would be in if it were a loadable module, hereafter
> referred to as <kmodfile>). This object name can be used to
> identify objects in the kernel compile because any C or assembler
> code that ends up into a built-in module will have the option
> -DKBUILD_MODFILE=<kmodfile> present in its build command, and those
> can be found in the .<obj>.cmd file in the kernel build tree.
>
> If an object is part of multiple modules, they will all be listed
> in the KBUILD_MODFILE option argument.
>
> This allows us to conclusively determine whether an object in the
> kernel build belong to any modules, and which.
>
> 2. The vmlinux.map is parsed next to determine the base address of each
> top level section so that all addresses into the section can be
> turned into offsets. This makes it possible to handle sections
> getting loaded at different addresses at system boot.
>
> We also determine an 'anchor' symbol at the beginning of each
> section to make it possible to calculate the true base address of
> a section at runtime (i.e. symbol address - symbol offset).
>
> We collect start addresses of sections that are included in the top
> level section. This is used when vmlinux is linked using vmlinux.o,
> because in that case, we need to look at the vmlinux.o linker map to
> know what object a symbol is found in.
>
> And finally, we process each symbol that is listed in vmlinux.map
> (or vmlinux.o.map) based on the following structure:
>
> vmlinux linked from vmlinux.a:
>
> vmlinux.map:
> <top level section>
> <included section> -- might be same as top level section)
> <object> -- built-in association known
> <symbol> -- belongs to module(s) object belongs to
> ...
>
> vmlinux linked from vmlinux.o:
>
> vmlinux.map:
> <top level section>
> <included section> -- might be same as top level section)
> vmlinux.o -- need to use vmlinux.o.map
> <symbol> -- ignored
> ...
>
> vmlinux.o.map:
> <section>
> <object> -- built-in association known
> <symbol> -- belongs to module(s) object belongs to
> ...
>
> 3. As sections, objects, and symbols are processed, offset ranges are
> constructed in a straight-forward way:
>
> - If the symbol belongs to one or more built-in modules:
> - If we were working on the same module(s), extend the range
> to include this object
> - If we were working on another module(s), close that range,
> and start the new one
> - If the symbol does not belong to any built-in modules:
> - If we were working on a module(s) range, close that range
>
> Signed-off-by: Kris Van Hees <kris.van.hees@...cle.com>
> Reviewed-by: Nick Alcock <nick.alcock@...cle.com>
> Reviewed-by: Alan Maguire <alan.maguire@...cle.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
> Tested-by: Sam James <sam@...too.org>
> ---
>
> Notes:
> Changes since v9:
> - Reverted support for build directory as optional 4th argument.
> - Added modules.builtin.ranges and vmlinux.o.map to CLEAN_FILES.
> - Fixed support for sparc64.
>
> Changes since v8:
> - Added support for built-in Rust modules.
> - Added optional 4th argument to specify kernel build directory.
>
> Changes since v7:
> - Removed extra close(fn).
> - Make CONFIG_BUILTIN_MODULE_RANGES depend on !lTO.
>
> Changes since v6:
> - Applied Masahiro Yamada's suggestions (Kconfig, makefile, script).
>
> Changes since v5:
> - Removed unnecessary compatibility info from option description.
>
> Changes since v4:
> - Improved commit description to explain the why and how.
> - Documented dependency on GNU AWK for CONFIG_BUILTIN_MODULE_RANGES.
> - Improved comments in generate_builtin_ranges.awk
> - Improved logic in generate_builtin_ranges.awk to handle incorrect
> object size information in linker maps
>
> Changes since v3:
> - Consolidated patches 2 through 5 into a single patch
> - Move CONFIG_BUILTIN_MODULE_RANGES to Kconfig.debug
> - Make CONFIG_BUILTIN_MODULE_RANGES select CONFIG_VMLINUX_MAP
> - Disable CONFIG_BUILTIN_MODULE_RANGES if CONFIG_LTO_CLANG_(FULL|THIN)=y
> - Support LLVM (lld) compiles in generate_builtin_ranges.awk
> - Support CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y
>
> Changes since v2:
> - Add explicit dependency on FTRACE for CONFIG_BUILTIN_MODULE_RANGES
> - 1st arg to generate_builtin_ranges.awk is now modules.builtin.modinfo
> - Switched from using modules.builtin.objs to parsing .*.cmd files
> - Parse data from .*.cmd in generate_builtin_ranges.awk
> - Use $(real-prereqs) rather than $(filter-out ...)
> ---
>
> Documentation/process/changes.rst | 7 +
> Makefile | 1 +
> lib/Kconfig.debug | 15 +
> scripts/Makefile.vmlinux | 18 +
> scripts/Makefile.vmlinux_o | 3 +
> scripts/generate_builtin_ranges.awk | 508 ++++++++++++++++++++++++++++
> 6 files changed, 552 insertions(+)
> create mode 100755 scripts/generate_builtin_ranges.awk
>
> diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
> index 3fc63f27c226..00f1ed7c59c3 100644
> --- a/Documentation/process/changes.rst
> +++ b/Documentation/process/changes.rst
> @@ -64,6 +64,7 @@ GNU tar 1.28 tar --version
> gtags (optional) 6.6.5 gtags --version
> mkimage (optional) 2017.01 mkimage --version
> Python (optional) 3.5.x python3 --version
> +GNU AWK (optional) 5.1.0 gawk --version
> ====================== =============== ========================================
>
> .. [#f1] Sphinx is needed only to build the Kernel documentation
> @@ -192,6 +193,12 @@ platforms. The tool is available via the ``u-boot-tools`` package or can be
> built from the U-Boot source code. See the instructions at
> https://docs.u-boot.org/en/latest/build/tools.html#building-tools-for-linux
>
> +GNU AWK
> +-------
> +
> +GNU AWK is needed if you want kernel builds to generate address range data for
> +builtin modules (CONFIG_BUILTIN_MODULE_RANGES).
> +
> System utilities
> ****************
>
> diff --git a/Makefile b/Makefile
> index d57cfc6896b8..ec98a1e5b257 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1482,6 +1482,7 @@ endif # CONFIG_MODULES
> # Directories & files removed with 'make clean'
> CLEAN_FILES += vmlinux.symvers modules-only.symvers \
> modules.builtin modules.builtin.modinfo modules.nsdeps \
> + modules.builtin.ranges vmlinux.o.map \
> compile_commands.json rust/test \
> rust-project.json .vmlinux.objs .vmlinux.export.c
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index a30c03a66172..5e2f30921cb2 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -571,6 +571,21 @@ config VMLINUX_MAP
> pieces of code get eliminated with
> CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
>
> +config BUILTIN_MODULE_RANGES
> + bool "Generate address range information for builtin modules"
> + depends on !LTO
> + depends on VMLINUX_MAP
> + help
> + When modules are built into the kernel, there will be no module name
> + associated with its symbols in /proc/kallsyms. Tracers may want to
> + identify symbols by module name and symbol name regardless of whether
> + the module is configured as loadable or not.
> +
> + This option generates modules.builtin.ranges in the build tree with
> + offset ranges (per ELF section) for the module(s) they belong to.
> + It also records an anchor symbol to determine the load address of the
> + section.
> +
> config DEBUG_FORCE_WEAK_PER_CPU
> bool "Force weak per-cpu definitions"
> depends on DEBUG_KERNEL
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index 5ceecbed31eb..dfb408aa19c6 100644
> --- a/scripts/Makefile.vmlinux
> +++ b/scripts/Makefile.vmlinux
> @@ -33,6 +33,24 @@ targets += vmlinux
> vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
> +$(call if_changed_dep,link_vmlinux)
>
> +# module.builtin.ranges
> +# ---------------------------------------------------------------------------
> +ifdef CONFIG_BUILTIN_MODULE_RANGES
> +__default: modules.builtin.ranges
> +
> +quiet_cmd_modules_builtin_ranges = GEN $@
> + cmd_modules_builtin_ranges = $(real-prereqs) > $@
> +
> +targets += modules.builtin.ranges
> +modules.builtin.ranges: $(srctree)/scripts/generate_builtin_ranges.awk \
> + modules.builtin vmlinux.map vmlinux.o.map FORCE
> + $(call if_changed,modules_builtin_ranges)
> +
> +vmlinux.map: vmlinux
> + @:
> +
> +endif
> +
> # Add FORCE to the prerequisites of a target to force it to be always rebuilt.
> # ---------------------------------------------------------------------------
>
> diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
> index d64070b6b4bc..0b6e2ebf60dc 100644
> --- a/scripts/Makefile.vmlinux_o
> +++ b/scripts/Makefile.vmlinux_o
> @@ -45,9 +45,12 @@ objtool-args = $(vmlinux-objtool-args-y) --link
> # Link of vmlinux.o used for section mismatch analysis
> # ---------------------------------------------------------------------------
>
> +vmlinux-o-ld-args-$(CONFIG_BUILTIN_MODULE_RANGES) += -Map=$@...p
> +
> quiet_cmd_ld_vmlinux.o = LD $@
> cmd_ld_vmlinux.o = \
> $(LD) ${KBUILD_LDFLAGS} -r -o $@ \
> + $(vmlinux-o-ld-args-y) \
> $(addprefix -T , $(initcalls-lds)) \
> --whole-archive vmlinux.a --no-whole-archive \
> --start-group $(KBUILD_VMLINUX_LIBS) --end-group \
> diff --git a/scripts/generate_builtin_ranges.awk b/scripts/generate_builtin_ranges.awk
> new file mode 100755
> index 000000000000..b9ec761b3bef
> --- /dev/null
> +++ b/scripts/generate_builtin_ranges.awk
> @@ -0,0 +1,508 @@
> +#!/usr/bin/gawk -f
This forces the gawk to be found always in /usr/bin. For systems where gawk can
be located in other places, can we change the Shebang to:
diff --git a/scripts/generate_builtin_ranges.awk b/scripts/generate_builtin_ranges.awk
index b9ec761b3bef..886251c8d3f7 100755
--- a/scripts/generate_builtin_ranges.awk
+++ b/scripts/generate_builtin_ranges.awk
@@ -1,4 +1,4 @@
-#!/usr/bin/gawk -f
+#!/usr/bin/env gawk -f
# SPDX-License-Identifier: GPL-2.0
# generate_builtin_ranges.awk: Generate address range data for builtin modules
# Written by Kris Van Hees <kris.van.hees@...cle.com>
Not sure if it's too late? in that case I can send a patch to change this.
Daniel
> +# SPDX-License-Identifier: GPL-2.0
> +# generate_builtin_ranges.awk: Generate address range data for builtin modules
> +# Written by Kris Van Hees <kris.van.hees@...cle.com>
> +#
> +# Usage: generate_builtin_ranges.awk modules.builtin vmlinux.map \
> +# vmlinux.o.map > modules.builtin.ranges
> +#
> +
> +# Return the module name(s) (if any) associated with the given object.
> +#
> +# If we have seen this object before, return information from the cache.
> +# Otherwise, retrieve it from the corresponding .cmd file.
> +#
> +function get_module_info(fn, mod, obj, s) {
> + if (fn in omod)
> + return omod[fn];
> +
> + if (match(fn, /\/[^/]+$/) == 0)
> + return "";
> +
> + obj = fn;
> + mod = "";
> + fn = substr(fn, 1, RSTART) "." substr(fn, RSTART + 1) ".cmd";
> + if (getline s <fn == 1) {
> + if (match(s, /DKBUILD_MODFILE=['"]+[^'"]+/) > 0) {
> + mod = substr(s, RSTART + 16, RLENGTH - 16);
> + gsub(/['"]/, "", mod);
> + } else if (match(s, /RUST_MODFILE=[^ ]+/) > 0)
> + mod = substr(s, RSTART + 13, RLENGTH - 13);
> + }
> + close(fn);
> +
> + # A single module (common case) also reflects objects that are not part
> + # of a module. Some of those objects have names that are also a module
> + # name (e.g. core). We check the associated module file name, and if
> + # they do not match, the object is not part of a module.
> + if (mod !~ / /) {
> + if (!(mod in mods))
> + mod = "";
> + }
> +
> + gsub(/([^/ ]*\/)+/, "", mod);
> + gsub(/-/, "_", mod);
> +
> + # At this point, mod is a single (valid) module name, or a list of
> + # module names (that do not need validation).
> + omod[obj] = mod;
> +
> + return mod;
> +}
> +
> +# Update the ranges entry for the given module 'mod' in section 'osect'.
> +#
> +# We use a modified absolute start address (soff + base) as index because we
> +# may need to insert an anchor record later that must be at the start of the
> +# section data, and the first module may very well start at the same address.
> +# So, we use (addr << 1) + 1 to allow a possible anchor record to be placed at
> +# (addr << 1). This is safe because the index is only used to sort the entries
> +# before writing them out.
> +#
> +function update_entry(osect, mod, soff, eoff, sect, idx) {
> + sect = sect_in[osect];
> + idx = sprintf("%016x", (soff + sect_base[osect]) * 2 + 1);
> + entries[idx] = sprintf("%s %08x-%08x %s", sect, soff, eoff, mod);
> + count[sect]++;
> +}
> +
> +# (1) Build a lookup map of built-in module names.
> +#
> +# The first file argument is used as input (modules.builtin).
> +#
> +# Lines will be like:
> +# kernel/crypto/lzo-rle.ko
> +# and we record the object name "crypto/lzo-rle".
> +#
> +ARGIND == 1 {
> + sub(/kernel\//, ""); # strip off "kernel/" prefix
> + sub(/\.ko$/, ""); # strip off .ko suffix
> +
> + mods[$1] = 1;
> + next;
> +}
> +
> +# (2) Collect address information for each section.
> +#
> +# The second file argument is used as input (vmlinux.map).
> +#
> +# We collect the base address of the section in order to convert all addresses
> +# in the section into offset values.
> +#
> +# We collect the address of the anchor (or first symbol in the section if there
> +# is no explicit anchor) to allow users of the range data to calculate address
> +# ranges based on the actual load address of the section in the running kernel.
> +#
> +# We collect the start address of any sub-section (section included in the top
> +# level section being processed). This is needed when the final linking was
> +# done using vmlinux.a because then the list of objects contained in each
> +# section is to be obtained from vmlinux.o.map. The offset of the sub-section
> +# is recorded here, to be used as an addend when processing vmlinux.o.map
> +# later.
> +#
> +
> +# Both GNU ld and LLVM lld linker map format are supported by converting LLVM
> +# lld linker map records into equivalent GNU ld linker map records.
> +#
> +# The first record of the vmlinux.map file provides enough information to know
> +# which format we are dealing with.
> +#
> +ARGIND == 2 && FNR == 1 && NF == 7 && $1 == "VMA" && $7 == "Symbol" {
> + map_is_lld = 1;
> + if (dbg)
> + printf "NOTE: %s uses LLVM lld linker map format\n", FILENAME >"/dev/stderr";
> + next;
> +}
> +
> +# (LLD) Convert a section record fronm lld format to ld format.
> +#
> +# lld: ffffffff82c00000 2c00000 2493c0 8192 .data
> +# ->
> +# ld: .data 0xffffffff82c00000 0x2493c0 load address 0x0000000002c00000
> +#
> +ARGIND == 2 && map_is_lld && NF == 5 && /[0-9] [^ ]+$/ {
> + $0 = $5 " 0x"$1 " 0x"$3 " load address 0x"$2;
> +}
> +
> +# (LLD) Convert an anchor record from lld format to ld format.
> +#
> +# lld: ffffffff81000000 1000000 0 1 _text = .
> +# ->
> +# ld: 0xffffffff81000000 _text = .
> +#
> +ARGIND == 2 && map_is_lld && !anchor && NF == 7 && raw_addr == "0x"$1 && $6 == "=" && $7 == "." {
> + $0 = " 0x"$1 " " $5 " = .";
> +}
> +
> +# (LLD) Convert an object record from lld format to ld format.
> +#
> +# lld: 11480 11480 1f07 16 vmlinux.a(arch/x86/events/amd/uncore.o):(.text)
> +# ->
> +# ld: .text 0x0000000000011480 0x1f07 arch/x86/events/amd/uncore.o
> +#
> +ARGIND == 2 && map_is_lld && NF == 5 && $5 ~ /:\(/ {
> + gsub(/\)/, "");
> + sub(/ vmlinux\.a\(/, " ");
> + sub(/:\(/, " ");
> + $0 = " "$6 " 0x"$1 " 0x"$3 " " $5;
> +}
> +
> +# (LLD) Convert a symbol record from lld format to ld format.
> +#
> +# We only care about these while processing a section for which no anchor has
> +# been determined yet.
> +#
> +# lld: ffffffff82a859a4 2a859a4 0 1 btf_ksym_iter_id
> +# ->
> +# ld: 0xffffffff82a859a4 btf_ksym_iter_id
> +#
> +ARGIND == 2 && map_is_lld && sect && !anchor && NF == 5 && $5 ~ /^[_A-Za-z][_A-Za-z0-9]*$/ {
> + $0 = " 0x"$1 " " $5;
> +}
> +
> +# (LLD) We do not need any other ldd linker map records.
> +#
> +ARGIND == 2 && map_is_lld && /^[0-9a-f]{16} / {
> + next;
> +}
> +
> +# (LD) Section records with just the section name at the start of the line
> +# need to have the next line pulled in to determine whether it is a
> +# loadable section. If it is, the next line will contains a hex value
> +# as first and second items.
> +#
> +ARGIND == 2 && !map_is_lld && NF == 1 && /^[^ ]/ {
> + s = $0;
> + getline;
> + if ($1 !~ /^0x/ || $2 !~ /^0x/)
> + next;
> +
> + $0 = s " " $0;
> +}
> +
> +# (LD) Object records with just the section name denote records with a long
> +# section name for which the remainder of the record can be found on the
> +# next line.
> +#
> +# (This is also needed for vmlinux.o.map, when used.)
> +#
> +ARGIND >= 2 && !map_is_lld && NF == 1 && /^ [^ \*]/ {
> + s = $0;
> + getline;
> + $0 = s " " $0;
> +}
> +
> +# Beginning a new section - done with the previous one (if any).
> +#
> +ARGIND == 2 && /^[^ ]/ {
> + sect = 0;
> +}
> +
> +# Process a loadable section (we only care about .-sections).
> +#
> +# Record the section name and its base address.
> +# We also record the raw (non-stripped) address of the section because it can
> +# be used to identify an anchor record.
> +#
> +# Note:
> +# Since some AWK implementations cannot handle large integers, we strip off the
> +# first 4 hex digits from the address. This is safe because the kernel space
> +# is not large enough for addresses to extend into those digits. The portion
> +# to strip off is stored in addr_prefix as a regexp, so further clauses can
> +# perform a simple substitution to do the address stripping.
> +#
> +ARGIND == 2 && /^\./ {
> + # Explicitly ignore a few sections that are not relevant here.
> + if ($1 ~ /^\.orc_/ || $1 ~ /_sites$/ || $1 ~ /\.percpu/)
> + next;
> +
> + # Sections with a 0-address can be ignored as well.
> + if ($2 ~ /^0x0+$/)
> + next;
> +
> + raw_addr = $2;
> + addr_prefix = "^" substr($2, 1, 6);
> + base = $2;
> + sub(addr_prefix, "0x", base);
> + base = strtonum(base);
> + sect = $1;
> + anchor = 0;
> + sect_base[sect] = base;
> + sect_size[sect] = strtonum($3);
> +
> + if (dbg)
> + printf "[%s] BASE %016x\n", sect, base >"/dev/stderr";
> +
> + next;
> +}
> +
> +# If we are not in a section we care about, we ignore the record.
> +#
> +ARGIND == 2 && !sect {
> + next;
> +}
> +
> +# Record the first anchor symbol for the current section.
> +#
> +# An anchor record for the section bears the same raw address as the section
> +# record.
> +#
> +ARGIND == 2 && !anchor && NF == 4 && raw_addr == $1 && $3 == "=" && $4 == "." {
> + anchor = sprintf("%s %08x-%08x = %s", sect, 0, 0, $2);
> + sect_anchor[sect] = anchor;
> +
> + if (dbg)
> + printf "[%s] ANCHOR %016x = %s (.)\n", sect, 0, $2 >"/dev/stderr";
> +
> + next;
> +}
> +
> +# If no anchor record was found for the current section, use the first symbol
> +# in the section as anchor.
> +#
> +ARGIND == 2 && !anchor && NF == 2 && $1 ~ /^0x/ && $2 !~ /^0x/ {
> + addr = $1;
> + sub(addr_prefix, "0x", addr);
> + addr = strtonum(addr) - base;
> + anchor = sprintf("%s %08x-%08x = %s", sect, addr, addr, $2);
> + sect_anchor[sect] = anchor;
> +
> + if (dbg)
> + printf "[%s] ANCHOR %016x = %s\n", sect, addr, $2 >"/dev/stderr";
> +
> + next;
> +}
> +
> +# The first occurrence of a section name in an object record establishes the
> +# addend (often 0) for that section. This information is needed to handle
> +# sections that get combined in the final linking of vmlinux (e.g. .head.text
> +# getting included at the start of .text).
> +#
> +# If the section does not have a base yet, use the base of the encapsulating
> +# section.
> +#
> +ARGIND == 2 && sect && NF == 4 && /^ [^ \*]/ && !($1 in sect_addend) {
> + if (!($1 in sect_base)) {
> + sect_base[$1] = base;
> +
> + if (dbg)
> + printf "[%s] BASE %016x\n", $1, base >"/dev/stderr";
> + }
> +
> + addr = $2;
> + sub(addr_prefix, "0x", addr);
> + addr = strtonum(addr);
> + sect_addend[$1] = addr - sect_base[$1];
> + sect_in[$1] = sect;
> +
> + if (dbg)
> + printf "[%s] ADDEND %016x - %016x = %016x\n", $1, addr, base, sect_addend[$1] >"/dev/stderr";
> +
> + # If the object is vmlinux.o then we will need vmlinux.o.map to get the
> + # actual offsets of objects.
> + if ($4 == "vmlinux.o")
> + need_o_map = 1;
> +}
> +
> +# (3) Collect offset ranges (relative to the section base address) for built-in
> +# modules.
> +#
> +# If the final link was done using the actual objects, vmlinux.map contains all
> +# the information we need (see section (3a)).
> +# If linking was done using vmlinux.a as intermediary, we will need to process
> +# vmlinux.o.map (see section (3b)).
> +
> +# (3a) Determine offset range info using vmlinux.map.
> +#
> +# Since we are already processing vmlinux.map, the top level section that is
> +# being processed is already known. If we do not have a base address for it,
> +# we do not need to process records for it.
> +#
> +# Given the object name, we determine the module(s) (if any) that the current
> +# object is associated with.
> +#
> +# If we were already processing objects for a (list of) module(s):
> +# - If the current object belongs to the same module(s), update the range data
> +# to include the current object.
> +# - Otherwise, ensure that the end offset of the range is valid.
> +#
> +# If the current object does not belong to a built-in module, ignore it.
> +#
> +# If it does, we add a new built-in module offset range record.
> +#
> +ARGIND == 2 && !need_o_map && /^ [^ ]/ && NF == 4 && $3 != "0x0" {
> + if (!(sect in sect_base))
> + next;
> +
> + # Turn the address into an offset from the section base.
> + soff = $2;
> + sub(addr_prefix, "0x", soff);
> + soff = strtonum(soff) - sect_base[sect];
> + eoff = soff + strtonum($3);
> +
> + # Determine which (if any) built-in modules the object belongs to.
> + mod = get_module_info($4);
> +
> + # If we are processing a built-in module:
> + # - If the current object is within the same module, we update its
> + # entry by extending the range and move on
> + # - Otherwise:
> + # + If we are still processing within the same main section, we
> + # validate the end offset against the start offset of the
> + # current object (e.g. .rodata.str1.[18] objects are often
> + # listed with an incorrect size in the linker map)
> + # + Otherwise, we validate the end offset against the section
> + # size
> + if (mod_name) {
> + if (mod == mod_name) {
> + mod_eoff = eoff;
> + update_entry(mod_sect, mod_name, mod_soff, eoff);
> +
> + next;
> + } else if (sect == sect_in[mod_sect]) {
> + if (mod_eoff > soff)
> + update_entry(mod_sect, mod_name, mod_soff, soff);
> + } else {
> + v = sect_size[sect_in[mod_sect]];
> + if (mod_eoff > v)
> + update_entry(mod_sect, mod_name, mod_soff, v);
> + }
> + }
> +
> + mod_name = mod;
> +
> + # If we encountered an object that is not part of a built-in module, we
> + # do not need to record any data.
> + if (!mod)
> + next;
> +
> + # At this point, we encountered the start of a new built-in module.
> + mod_name = mod;
> + mod_soff = soff;
> + mod_eoff = eoff;
> + mod_sect = $1;
> + update_entry($1, mod, soff, mod_eoff);
> +
> + next;
> +}
> +
> +# If we do not need to parse the vmlinux.o.map file, we are done.
> +#
> +ARGIND == 3 && !need_o_map {
> + if (dbg)
> + printf "Note: %s is not needed.\n", FILENAME >"/dev/stderr";
> + exit;
> +}
> +
> +# (3) Collect offset ranges (relative to the section base address) for built-in
> +# modules.
> +#
> +
> +# (LLD) Convert an object record from lld format to ld format.
> +#
> +ARGIND == 3 && map_is_lld && NF == 5 && $5 ~ /:\(/ {
> + gsub(/\)/, "");
> + sub(/:\(/, " ");
> +
> + sect = $6;
> + if (!(sect in sect_addend))
> + next;
> +
> + sub(/ vmlinux\.a\(/, " ");
> + $0 = " "sect " 0x"$1 " 0x"$3 " " $5;
> +}
> +
> +# (3b) Determine offset range info using vmlinux.o.map.
> +#
> +# If we do not know an addend for the object's section, we are interested in
> +# anything within that section.
> +#
> +# Determine the top-level section that the object's section was included in
> +# during the final link. This is the section name offset range data will be
> +# associated with for this object.
> +#
> +# The remainder of the processing of the current object record follows the
> +# procedure outlined in (3a).
> +#
> +ARGIND == 3 && /^ [^ ]/ && NF == 4 && $3 != "0x0" {
> + osect = $1;
> + if (!(osect in sect_addend))
> + next;
> +
> + # We need to work with the main section.
> + sect = sect_in[osect];
> +
> + # Turn the address into an offset from the section base.
> + soff = $2;
> + sub(addr_prefix, "0x", soff);
> + soff = strtonum(soff) + sect_addend[osect];
> + eoff = soff + strtonum($3);
> +
> + # Determine which (if any) built-in modules the object belongs to.
> + mod = get_module_info($4);
> +
> + # If we are processing a built-in module:
> + # - If the current object is within the same module, we update its
> + # entry by extending the range and move on
> + # - Otherwise:
> + # + If we are still processing within the same main section, we
> + # validate the end offset against the start offset of the
> + # current object (e.g. .rodata.str1.[18] objects are often
> + # listed with an incorrect size in the linker map)
> + # + Otherwise, we validate the end offset against the section
> + # size
> + if (mod_name) {
> + if (mod == mod_name) {
> + mod_eoff = eoff;
> + update_entry(mod_sect, mod_name, mod_soff, eoff);
> +
> + next;
> + } else if (sect == sect_in[mod_sect]) {
> + if (mod_eoff > soff)
> + update_entry(mod_sect, mod_name, mod_soff, soff);
> + } else {
> + v = sect_size[sect_in[mod_sect]];
> + if (mod_eoff > v)
> + update_entry(mod_sect, mod_name, mod_soff, v);
> + }
> + }
> +
> + mod_name = mod;
> +
> + # If we encountered an object that is not part of a built-in module, we
> + # do not need to record any data.
> + if (!mod)
> + next;
> +
> + # At this point, we encountered the start of a new built-in module.
> + mod_name = mod;
> + mod_soff = soff;
> + mod_eoff = eoff;
> + mod_sect = osect;
> + update_entry(osect, mod, soff, mod_eoff);
> +
> + next;
> +}
> +
> +# (4) Generate the output.
> +#
> +# Anchor records are added for each section that contains offset range data
> +# records. They are added at an adjusted section base address (base << 1) to
> +# ensure they come first in the second records (see update_entry() above for
> +# more information).
> +#
> +# All entries are sorted by (adjusted) address to ensure that the output can be
> +# parsed in strict ascending address order.
> +#
> +END {
> + for (sect in count) {
> + if (sect in sect_anchor) {
> + idx = sprintf("%016x", sect_base[sect] * 2);
> + entries[idx] = sect_anchor[sect];
> + }
> + }
> +
> + n = asorti(entries, indices);
> + for (i = 1; i <= n; i++)
> + print entries[indices[i]];
> +}
> --
> 2.45.2
>
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